Gender Differences in Delay of Gratification: A Meta-Analysis Irwin W. Silverman Alicia Summers Radford University

Purpose: To analyze possible gender differences in delay of gratification  Are females more likely than males to be able to delay gratification?  Is there an age difference among delay of gratification results among females and males?  Do results support Bjorklund & Kipp’s hypothesis concerning selection pressures operating during evolution?

Issues to Consider How is delay of gratification assessed? -Choice between two rewards Small now or larger later if can wait -Choice between one or more rewards After choice made, cannot revoke -Continuous Measures-count of time waited to receive larger reward, or when more than one choice is made -Dichotomous Measures-when only one choice is made

Literature Review Up until Sept, 2002 Methods Electronic Sources using keyword phrase “delay of gratification” PsycINFO ERIC Search of bibliographies of studies found through database results For Dissertation Abstract found, only those which circulated without cost were used Studies 115 found 33 usable  38 Effect Sizes

Studies to Include Must be written in English Subjects recruited from general population Participants had to have been offered real instead of hypothetical choices Must provide information to calculate effect size for gender differences

Potential Moderators Type of assessment Dichotomous Continuous Age level of participants Preschool (3-5 years) Preschool/Elementary (3-11 years) Elementary (6-11 years) Adolescence/Adulthood (12-17/18+ years)

Dichotomous Measures Age LevelM95% CIQk Preschool Preschool/ Elementary Elementary Adolescence/ Adulthood Overall

Continuous Measures Age LevelM95% CIQk Preschool.108** Preschool/ Elementary.082** ***16 Elementary **6 Adolescence/ Adulthood.101** ***6 Overall.096*** ***23 * p <.05, **p <.01, ***p <.001

Results No overall gender difference For the dichotomous studies, none of the effect sizes were significant Means significantly larger for continuous, z = -2.45, p <.05 For the continuous studies, there was an overall effect size and all subgroups except Elementary age were significant Only Preschool age was generalizable, all other studies had too much variability and other moderators need to be considered No significant difference between age groups at any levels

Limitations of the Study Other potential moderators not mentioned: Type of reward Small effect sizes, may be due to small sample sizes Had to throw out nonsignificant studies of gender differences which may have affected overall effect size Didn’t search in all available databases Considered items as continuous even when only three choices

Conclusions regarding Bjorklund & Kipp’s Hypothesis From a sociobiological perspective, women should be better able to delay gratification than men Gender differences did favor females No evidence to support that delay of gratification intensifies with puberty There are other explanations for gender differences in delay of gratification